In the micro-fluidic field there is known a type of system comprising a channel, which includes two segments connected to one another by a valve. The valve usually includes a partition arranged along the channel to separate the two segments and a membrane of an elastomeric material connected to a wall of the channel in the area of two holes, each of which is arranged at an end of a respective segment in the area of the partition. The valve further comprises a pneumatic actuator, which is adapted: on one side, to create a depression so as to deform the membrane and, therefore, connect the two segments of the channel; on the other side, to exert a pressure to push the membrane against the wall of the channel so as to close the two holes and isolate the two segments.
Known valves and circuits of the above indicated type are for example disclosed in WO2008115626 (see in particular FIG. 2) and in WO2004061085 (see in particular FIGS. 1A-1E) and have several drawbacks.
A first series of drawbacks derives from the fact that the pneumatic actuator needs to always be active (both when the valve is to be opened, and when the valve is to be closed). This determines a high energy consumption and a considerable wear. It should also be noted that pneumatic actuators having the suitable size to create both a depression and a compression are relatively complex and expensive.
Furthermore, it should be noted that the preparation of this type of valves is often complex. Some of the problems in this connection are due to the fact that the membrane must often be selectively connected to the wall of the channel and not to the partition.
Patent documents EP1905514, DE19949912, WO9917749 disclose especially complex micro-fluidic systems comprising channels the geometrical structures of which is complicated and difficult to implement.
Further drawbacks of the state of the art are related to the fact that it is not always possible to correctly maintain the membrane in position and/or obtain an effective coupling between the membrane and the partition.